Internal-combustion rammer



INTERNAL-COMBUSTION RAMMER Filed June 7, 1947 3 Sheets-Sheet 1 July 17,1951 v. w. BREITENSTEIN EI'AL INTERNAL-COMBUSTION RAMMER Filed June 7,1947 3 Sheets-Sheet 2 a very much heavier rammer.

Patented July 17 1951 INTERNAL-COMBUSTION HAMMER Victor W. Breitenstein,Chicago, and Emmons R.

Boddinghouse, Evanston,

Francis N. Bard Ill. :assignors to Application June 7, 1947, Serial N0.753,2'70

.3 Claims.

This invention relates to -a rammer, and more particularly to a rammingor tamping device of the so-called leaping type, operated by internalcombustion.

While small hammers are sometimes used for tamping, heavy tampingor-ramming, as for example in back fill work, is preferably done withThe basic principles of rammers of the "leaping" type have heretoforebeen known, but certain defects have been present and such rammers havenot gone into commercial use in this country. Rammers of the type withwhich we are here concerned comprise a relatively heavy generallyvertical bodywhich would normally weigh in the neighborhood of 200pounds, and which leaps into the air as the result of an internalexplosion of ,a combustible mixture (as a gasoline-air mixture) underthe control of an operator, to come down with its full weight anddeliver a very efiective ramming blow.

"We have overcome previous defects and disadvantages of such rammers.One feature of the invention here being disclosed is in the provision ofa satisfactorily operative combustion chamber relief valve enabling thelower piston (and the connected foot) to return rapidly to normalposition, ready for the ramming blow,

at or near the top of the leap. Another feature of this invention is theprovision of protecting arrangements for the intake and relief valves,particularly a protective arrangement for the air intake valve of thecarburetor, obviating warpage, sticking and other difiicultiesheretofore encountered-with such valves. Another feature of the devicehere being disclosed is the provision of an improved gasoline feedarrangement enabling gravity feed of gasoline to the carburetor while atthe same time maintaining sufficient cooling between the gasoline tankand the combustion cylinder to prevent boiling of the gasoline. Yet afurther feature of this invention is the provision of an air intakeminimizing difficulties with dirt getting into the operative parts ofthe rammer. Other features and advantages will be apparent from thefollowing specification and the drawing, in which:

Fi ure 1 is a view, principally in side elevation, of one embodiment ofour invention; Figure 2 is a view, principally in vertical section alongthe .line 2-2 of Figure 1; Figure 3 is an enlarged fragmentary detailvertical sectional view of the upper portion of the device; 'Figure 4 isan enlarged fragmentary vertical sectional view of the combustionchamber and the valves associated .2 therewith; and Figure 5 is afragmentary vertical sectional view of the carburetor along the line 5-5of Figure 4.

Inasmuch as rammers of this general type have been the subject of anumber of earlier patents and their general principles of operation arewell known, the general construction and operation of the rammer will beonly briefly described.

The device comprises four principal portions which may be termed theupper'or head portion, here identified in general as A; a central bodyportion E, including the combustion chamber; ;a lower body portion C;and afoot portion D. The upper, central and lower body portions are hereshown as held together by tie rods 10 and H;

and the foot portion, together with the rod and rocate with respect tothe body portion.

If the rammer be assumed to be standing on the ground as illustrated inFigures -1 and 2, a rammingleap is effectedby the operator' by-pushingdown on the handle 12 and *then -releas-ing the same to effect anexplosion and leap, the operator continuing to hold onto the handle I2While the rammer is in the air in orderto'keep it under control, andrepeating the leaps as frequently as he may desire by operation on thehandle. Pushing down on the handle 12 onerates through the crossbar l3,overcoming the force of two springs (not shown but contained within thehead -A to balance out the weight :of the handle, upper piston andinterconnecting parts, and to normally keep these in uppermost position)to move therod l6 downwardly. This moves the valve H in the upper pistonl8 away from its seat, and then pushes the piston l8 downwardly, gasesremaining in the cylinder from the previous explosion-passing throughthe central opening Na in the upper piston during its downward movement.When the upper piston has reached the limit of .its downward movement(with its head substantially opposite the top of the inlet opening 19ain the cylinder 1-9) the'handle i2 would be moved upwardly. This closesthe valve i'l onto its seat and lifts the piston 18 up, creating avacuum in .the combustion chamber drawing in an air-gasoline mixturefrom the carburetor identified in general'as 29,'burned gasesformerly-in the cylinderandnow above the upper piston I8 being exhaustedto =ber 2-2 with which it cooperates) engages the shoulder 22a of themagneto operating member and moves it upwardly, rotating the shaft ofthe magneto, until it finally slips off of such shoulder at almost thetop of its movement. Rotation of the magneto rotor is then efiected by aspring (not shown) and a spark is delivered to the plug 23 and jumps thepoints thereof to ignite the mixture.

Since the upper piston 18 is at the upper limit of its travel by thistime, and the valve I! is closed, the expansion due to combustion in thecylinder i9 tends to separate the lower piston 24 and the upper pistonl8. Inasmuch as this lower piston 24 is rigidly connected to the rod 25,in turn rigidly connected to the foot 26, and this foot is standing onthe ground, there can be practically no downward movement of the piston24. Instead, the force of the explosion causes the upper piston 18 andthe whole body of the rammer to move upwardly into the air, the piston24 thus moving downwardly in the cylinder l9 during this relativemovement between the piston and cylinder. When the relative movement hascaused the top of the piston 24 to be below the exhaust ports 21a and211) the burned gases in the combustion chamber are exhausted and thespring 28 tends to return the piston 24 and foot 26 to a positionrelative to the body it) as shown in Figures 1 and 2. Since the body ofthe rammer is at this time normally a foot and a half to two feet in theair, the foot lifts up (raised by the spring 28) to return to its normalposition with respect to its body, and then the entire device falls backto rest on the ground to deliver a heavy ramming blow.

One of the defects heretofore found in machines of this character hasbeen in connection with the relative movement of the lower piston andbody, and particularly the speed of return again reducing the force ofthe ramming impact.

We have overcome this defect by provision of a supplementary exhaustarrangement, higher up in the cylinder, which is closed during theexplosion and downward movement of the piston 24, but open during theupward or return move- 1 ment thereof; and which is not open to thecylinder at the instant of explosion of the charge.

Referring now more particularly to Figure 4, it will be seen that thewall of the cylinder I9 is provided with a port 3| only slightly belowthe sealing rings of the piston 24 in its uppermost position. This port3| opens into a chamber cooperating with a valve seat 32a provided bythe housing 32. A valve 33 cooperates with this seat, being normallyurged toward an open position, as illustrated, by a spring 34. When thevalve is in this open position and the piston 24 is below the port 3|gases in the chamber may pass out through the port 3|, between the valveand its seat, and outthrough the opening 35 to atmosphere.

The relief valve 33, however, must be closed during the explosion anddownward movement of the piston 24 inorder to avoid loss of power andresultant diminishing of the leap; and yet this 4 valve must stand openduring upward movement of the piston 24, after the force of theexplosion has been spent, to relieve the pressure which would otherwiseretard return movement of the lower piston and foot.

Since the spring 28 beneath the lower piston 24 is a fairly strongspring, sufficient upward movement of the piston 24 to close off theports 27 may take place before the pressure in the combustion chamberhas dropped completely to atmosphere; in fact, there may be severalpounds per square inch pressure in the chamber at all times. We havefound it necessary to make the spring 34 of sufficient strength to openthe valve 33 even though there may be several pounds per square inchpressure on it. On the other hand, the spring must not be too strong orit will open the relief valve near the end of the explosion period, butbefore the piston 24 has gotten to its lowermost position in thecylinder; and this will result in a loss of jump. In fact, too heavy aspring 34 can result in the loss of almost half of the jump.

If the spring strength is properly proportioned with respect to the areaof the head of the valve 33, however, the relief valve will closeinstantly when the piston rings pass below the top of the port 3|, andremain closed until the spring 28 has bottomed or become solid, which wearrange to take place slightly before the bottom of the piston wouldotherwise strike the shoulder at the upper end of the lower body portionC, to protect these parts from damage; and then the relief valve 33 willopen, permitting unretarded return of the piston 24 until the rings havepassed the port 3!. Since the rings are practically at the upper limitof their movement at this time, no substantial compression takes placeabove the piston and the piston and foot return to uppermost position(relative to the body) rapidly. We have found that .a very goodrelationship between the spring 34 and the valve 33 is one which willjust open the valve, from an initially closed position, against apressure of between five and twenty pounds per square inch in thecylinder, one very satisfactory embodiment of our invention having thearrangement such that the valve 33 would just open against a pressure ofseven pounds per square inch.

If a spring of too great strength is used, as one opening the valve fromclosed position against a pressure of twenty pounds per square inch ormore, the valve does not close quickly enough when uncovered by the topring of the piston and may open before the explosion stroke is reallycompleted, reducing the efficiency and jump of the rammer. The simplepoppet valve arrangement can be used because of proper springproportioning; and by locating the port opening to this valve below thetop ring of the piston 24 in uppermost position the most efiicientoperation is obtained, there being no opening to the valve from thecylinder at the instant of explosion. Previous attempts to provide anauxiliary relief valve have incorporated a passageway opened to thecombustion chamber at all times, and complicated slide arrangementswhich stuck and were otherwise unsatisfactory after an extremely shortperiod of use.

Another difficulty heretofore encountered with rammers of this type hasbeen failure of the carburetor inlet valve, and we have provided aprotective arrangement. Referring now more particularly to Figures 4 and5, the carburetor and protective arrangement will be described.

Ma controlled by a needle valve t2 and communicating with a gasolinefeed pipe l3 leading up to an opening into the bottom of the gasolinetank 54, which is located at the top of the ram mer, this communicationbeing through a strainer device 45. In rammers of the type here beingdiscussed it has heretofore been general to show the fuel tank at thevery bottom of the body. generally with some kind of a capillary feed tothe carburetor which proved very unsatisfactory. Location :of the fueltank at the top of the ram-- mer body has heretofore been consideredundesirable, not only from .a weight distribution standpoint, but alsobecause the heat rising from the combustion chamber would, cause thegasoline to boil, with resultant vapor loss. particularly in hotweather. It has also proved imprac tical to mount the gasoline tanks atthe side of 1 the cylinder, as is done in some other internal combustiondevices, since these rammers are frequently used in backfill work innarrow trenches, or close to the side of a bank, where maintaining theoutside dimensions of the device at a minimum, and substantially uniformfrom top to bottom, are important.

We have found that we can locate the fuel tank at the top by so local,gasoline weight on one side of the center of the rammer by magneticweight on the other side and achieve proper balance; and that we canprovide an air cooled zone between the top of the cylinder and thebottom of the gasoline tank which prevents overheating. To be sure ofpositive air circulation between the cylinder head and the bottom of thegasoline tank we arrange air openings, as the air openings 5i? betweenthe ribs 5! supporting the fuel tank above the plate 353, as may be bestseen in Figures 1 and 3. By supporting a fuel tank on relatively thinribs direct heat conduction from the plate 36 is minimized; and much ofthe heat passing up the ribs is dissipated by the cooling effect of airtherearound. Positive movement of air in this space between the plate 39and the fuel tank M is effected primarily by the upward and downwardmovement of the parts carried by the center plunger iii, and to someextent by the intake of air for the carburetor through the sceen all andtube 45a, this latter being a flexible conduit leading from the intakesection on the top of the plate to the carburetor. When upward movementof the piston l8 has created a vacuum in the combustion chamber andlifted the valve 48 from its seat air flows down through the conduit 4-3and up around the valve All, drawin liquid gasoline through the orificeMa and mixing it with the air to provide combustible charge in knownmanner.

The principal advantage of using an air intake of the kind illustrated,however, is in minimizing difficulty with dirt particles getting intothe carburetor and into the body of the rammer. Tamping work throws up acloud of dirt, and direct air intake at the bottom of the carburetor isunsatisfactory. By locating the screen M5 on top of the plate 36 it isprotected from being struck directly by any dirt thrown up by thetamping action; and the screen serves to filter out small dust particlesfloating in the air. Use of a screen on an opening directly at the baseof the carburetor is impractical, as dirt thrown up by the tamping clogsit after a short period of operation.

In previous rammers the carburetor value All been exposed directly to'th'eheataef the :burning gases during the explosion-in the combustioncylinder, heating this valve substantially. Car-- bon formation can thustake place directly at the valve. In addition, the valve would beconsiderably heated and then on the next inlet stroke relatively coolgasoline "would contact one point of its periphery, cooling this onepoint very drastically, resulting in frequent warpage-of the valve withresultant failure to seat properly and shut off gasoline flow betweenintake operations.

We overcome these difficulties by providing-a protective valve 58between the carburetor valve and the combustion chamber, as may be bestL3. in Figure 4. During the intake operation ves 2% and it are both openand the air-gas mixture is sucked into the combustion chamber; andduring the explosion and the return movement of the piston at both ofthese valves are closed. During this time, however, the valve .48

provides a seal between the carburetor valve. All

and the combustion ases and the combustion heat. This has resulted ingreatly increasing the satisfactoriness of operation of the carburetor;in fact, practically rendering it trouble free. We have found itpreferable to make the upper valve of a somewhat greater area than thelower valve, preferably at least 50-35% ter in area; and to make thesprin load of upper valve slightly greater than that .of the lowervalve, proportionately to its area. We prefer to have thevspring-loading--area relationship of these valves such that it takes aslightly greater force to lift valve 48 from its seat, so that theinstant this valve lifts the carburetor valve it! immediately lifts; andso that, upon completion of the inlet stroke and at or before theinstant of the explosion taking place in the cylinder, the valve libcloses, if anything, slightly ahead of the valve lli. The valve springused in conjunction with the carburetor valve to must be quite light,preferably with a pressure of only a matter of ounces when the valve isclosed, and the use of a heavier spring on the valve 4%. eliminates lossof power which sometimes otherwise took place through bounce of theintake valve as the result of vibrations incident to operation of therammer. Moreover, the use of a smaller valve as the lower or carburetorvalve makes this lower opening more restricted than the upper one andresults in an increase of velocity of the air flowing past this valve,insuring positive drawing into the air stream of not only gasoline butalso of oil mixed with the gasoline in lubrication. In devices of thischaracter there has sometimes heretofore been a tendency for the oil notto pass on into the combustion cylinder in the desired ratio to thegasoline, as it was initially mixed in the fuel tank, but to separateout at the carburetor and leak out at this point without providing thenecessary lubrication in the working cylinder of the machine.

While I have shown and described certain emembodiments of my invention,it is to be understood that it is capable of many modifications.Changes, therefore, in the construction and arrangement may be madewithout departing from the spirit and scope of the invention asdisclosed in the appended claims.

We claim:

1. An internal combustion rammer of the character described, including:a body portion having a cylinder therein; a piston movable in saidcylinder; a ramming foot connected to and movable with said piston;means for delivering a combustible charge to said cylinder and ignitingthe charge to move the piston and foot downwardly relative to said bodyportion; a piston spring for returning the piston and foot relativelyupwardly; principal exhaust port means in said cylinder so located as tobe uncovered by the piston only near the end of its downward movement;an auxiliary exhaust arrangement consisting of only a single exhaustopening, located in said cylinder at such a point as to remain uncoveredby the piston during at least the major portion of its return movementeflfected by the spring but to be covered by the piston by the end ofits return movement; a poppet valve member for closing said exhaustopening this valve member being located in said opening so thatexplosion pressure admitted to said opening from the cylinder iseffective against its head to move it to closed position; and a springnormally urging said valve member to open position, said spring beingweak enough to permit the pressure in the cylinder during the entireexplosion stroke to keep the valve member closed until the exhaust portmeans has been uncovered by the piston but strong enough to keep thevalve member open against scavenging pressure during return movement ofthe piston, whereby spent gases exhaust through said same openingthrough which explosion pressure gases were admitted to actuate saidvalve.

2. Apparatus of the character claimed in claim 1, wherein the valvesprin is of such a strength 8 as to just open the valve member, fromclosed position, against a pressure thereon of between 5 and 20 lbs. persquare inch.

3. Apparatus of the character claimed in claim 1, wherein the valvespring is of such a strength as to just open the valve member, fromclosed position, against a pressure thereon of about 7 lbs. per squareinch.

VICTOR W. BREITENSTEIN.

EM'MONS R. BODDINGI-IOUSE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 911,187 White et al Feb. 2, 19091,034,053 Wyer July 30, 1912 1,647,554 Trapnell Nov. 1, 1927 1,666,981Somervell Apr. 24, 1928 1,920,765 Rasch Aug. 1, 1933 2,027,080 WilcoxJan. 7, 1936 2,07 ,266 Kiecksee Mar. 2, 1937 2,112,672 Lasley Mar. 29,1938 2,214,800 Smith Sept. 17, 1940 2,292,942 Horner Aug. 11, 19422,333,419 Fitch Nov. 2, 1943 FOREIGN PATENTS Number Country Date 395,524Great Britain July 20, 1933 749,121 France May 2, 1933

